feat: add survey invite schemas and token field

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/app/schemas/survey.py

@@ -0,0 +1,46 @@
+"""Schemas for FlowPilot survey submission."""
+from datetime import datetime
+from typing import Any, Optional
+from pydantic import BaseModel, Field
+
+
+class SurveySubmission(BaseModel):
+    """Incoming survey response from the public form."""
+    respondent_name: Optional[str] = Field(None, max_length=255)
+    responses: dict[str, Any] = Field(
+        ...,
+        description="Question ID -> answer mapping. Values can be strings, lists, or numbers.",
+    )
+    token: Optional[str] = Field(None, description="Invite token for tracking")
+
+
+class SurveySubmissionResponse(BaseModel):
+    """Response after successful submission."""
+    message: str = "Thank you for your response!"
+    id: str
+
+
+class SurveyInviteCreate(BaseModel):
+    """Create a new survey invite."""
+    recipient_name: str = Field(..., min_length=1, max_length=255)
+    recipient_email: Optional[str] = Field(None, max_length=255)
+    send_email: bool = False
+
+
+class SurveyInviteResponse(BaseModel):
+    """Invite details returned to admin."""
+    id: str
+    token: str
+    recipient_name: str
+    recipient_email: Optional[str]
+    status: str
+    email_sent: bool
+    created_at: datetime
+    completed_at: Optional[datetime]
+    survey_url: str
+
+
+class SurveyInviteStatus(BaseModel):
+    """Public invite status check — minimal info."""
+    name: str
+    status: str